Fix convection issues when meteorology is Grell Freitas scheme

[yuanjianz]

Name and Institution (Required)

Name: Yuanjian Zhang Institution: WashU

Describe the update

See discussion https://github.com/geoschem/geos-chem/issues/1409

GEOS-IT and GEOS-FP after Jun 2020 switch to Grell Freitas convection from RAS. Some meterology field definitions are changed. This update accommodates these fields to geos-chem convection.

Reported by @viral211 first:

There was an error in archiving the convective precipitation fields (PFLCU and PFICU) in our GEOS-IT and GEOS-FP data after the switch to Grell-Freitas (the fields are just set to zero). These fields are used in GEOS-Chem to calculate convective washout and re-evaporation

@yuanjianz:

Since DQRCU by definition is changed to net precipitation (MERRA-2 definition DQRCU minus layer-wise re-evaporation), do you think we should add layer-wise REEVAP back to match the DQRCU for determining cloud base height? It may lower the cloud base height somehow, given it seems some gas tracer is substantially below observation constraint?

Expected changes

Lower cloud base and restored washout in geos-chem convection driven by GEOS-IT and GEOS-FP after Jun 2020.

Related Github Issue

https://github.com/geoschem/geos-chem/issues/2469